DNS Debacle

The past few weeks have been challenging. 6 months ago I inherited a network of five machines. One NS with a seperate backup, Two webservers, a DB server and a mail server. There was no need to move anything, the plan was to leave it all with the hosting environment it's currently in.  However, some developments have made a move to new servers necessary.

The first thing I had to do was find out what domains we hosted. 

  1. grep -i servername /etc/httpd/sites-enabled/* | awk '{print $3}' | sort | uniq > /home/v.flesouras/all_document_roots

That produced output that looks like this:

  1. 4noweeds.com
  2. acnmwa.org
  3. adairdentistry.com
  4. adoptarkids.org
  5. after-sort.net
  6. after-sort.org
  7. aftersort.net
  8. aidtemps.com
  9. allcleanusa.com

Using the large list - about 2200 domains, I used a script that does a DNS query

  1. #!/bin/bash
  2.  
  3. for dom in cat ./domainslist.txt
  4. do
  5.  
  6. result=$(dig +noall +answer $domains | awk '{print $5}')
  7.  
  8. if [ "$result" != '' ];then
  9.  
  10. echo "$dom" >> /home/xxxx/havingA.txt
  11.  
  12. else
  13.  
  14. echo "$dom" >> /home/xxxx/havingNoA.txt
  15.  
  16. fi
  17.  
  18. done

and returns

  1. 1stlutheran.com. 2947 IN A 184.168.204.1
  2. 30a-foreclosures.com. 124 IN A 72.3.186.100
  3. 4morerice.com. 124 IN A 72.3.186.100
  4. 4noweeds.com. 124 IN A 64.91.228.168
  5. 870935ride.com. 1149 IN A 69.2.210.229
  6. aaasold.com. 2949 IN A 64.202.189.170
  7. acnmwa.org. 124 IN A 64.91.228.168
  8. adairdentistry.com. 124 IN A 64.91.228.168
  9. adamsrestaurants.com. 124 IN A 72.3.186.13
  10. adoptarkids.org. 124 IN A 72.3.186.16
  11. adultandbabydiapers.com. 125 IN A 72.3.186.15
  12. after-sort.com. 125 IN A 72.3.186.13
  13. after-sort.net. 125 IN A 72.3.186.13
  14. after-sort.org. 125 IN A 72.3.186.13
  15. aftersort.com. 3550 IN A 174.120.82.5
  16. aftersort.net. 125 IN A 72.3.186.13

Which with a bit of regex in vim can be parsed down to simply "domain.com 72.3.186.15" Once you have "domain ip" list, you can eliminate lines that don't correspond to your subnet. You're left with a list of domains that by verification with DNS, accurately reflect the domains you host.

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The man behind the curtain

Vincent is above all things, a dad. Time that is not spent learning what it is to be a dad and enjoying that journey is spent immersed in the ever evolving realm of all things digital.  He likes to tinker with anything electronic. Often that means making his android phone do complex, but silly things.  He likes to experiment with new languages and stays current on new development strategies and methods. His life is often consumed with being a middling squire and apprentice Armorer